Both wild‐ and hatchery‐reared brown trout Salmotrutta, 18 months of age and of the same genetic origin, responded with increased heart rates (tachycardia) to a simulated predator attack on 2 consecutive days. Brown trout reared in the hatchery showed a more rapidly induced tachycardia compared with wild‐reared fish at day 1, but not day 2. During an undisturbed period several hours after attacks, hatchery‐reared brown trout maintained higher heart rates compared to wild‐reared fish on both days. Behavioural responses to the attack were very low for all fish, although hatchery‐reared fish tended to be more active than wild fish after the attack day 2. The observed differences may have had a genetic background caused by different selection regimes in the hatchery‐ and wild‐rearing environments, or could have been due to different phenotypic responses in the two environments.
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Document Type: Regular Paper
Göteborg University, Department of Zoology/Animal Ecology, Box 463, SE-405 30, Göteborg, Sweden,
Division of Population Genetics, Department of Zoology, Stockholm University, SE-106 91 Stockholm, Sweden
Publication date: 2005-10-01